package deng.wubo.util;


import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.interfaces.DecodedJWT;

import java.io.UnsupportedEncodingException;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class JWTUtil {
    // 过期时间5分钟
    private static final long EXPIRE_TIME = 5*60*1000;

    /**
     * 校验token是否正确
     * @param token 密钥
     * @param secret 用户的密码
     * @return 是否正确
     */

    public static boolean verify(String token,String username, String secret){
        try{

            Algorithm algorithm = Algorithm.HMAC256(secret);
            JWTVerifier verifier = JWT.require(algorithm)
                    .withClaim("username",username)
                    .build();

            DecodedJWT jwt = verifier.verify(token);
            return true;

        }catch (Exception e){
            return false;
        }


    }




    /**
     * 获得token中的信息无需secret解密也能获得
     * @return token中包含的用户名
     */
    public static String getUsername(String token){

        try{
            DecodedJWT jwt = JWT.decode(token);
            return jwt.getClaim("username").asString();
        }catch (JWTDecodeException e){
            return null;
        }
    }


    /**
     * 生成签名,5min后过期
     * @param username 用户名
     * @param secret 用户的密码
     * @return 加密的token
     */

    public static Object sign(String username,String secret){
        Map<String,Object> result = new HashMap<>();
        try {
            Date date = new Date(System.currentTimeMillis()+EXPIRE_TIME);
            Algorithm algorithm = Algorithm.HMAC256(secret);
            String token= JWT.create()
                    .withClaim("username",username)
                    .withExpiresAt(date)
                    .sign(algorithm);


            result.put("expire",EXPIRE_TIME);
            result.put("token",token);
            return result;


        }catch (UnsupportedEncodingException e){
            return null;
        }

    }

}
